Friday, January 16, 2015

"Humanity’s Future: Below Replacement Fertility?"

Reading my Inter Press Service RSS feed this evening, I came across Joseph Chamie's essay arguing that, on current trends, the entire world may shift to below-replacement fertility in a surprisingly short time. At the end of his analysis, he concludes that this trend is likely to spread worldwide.

According to United Nations medium-variant population projections, by mid-century the number of countries with below replacement fertility is expected to nearly double, reaching 139 countries. Together those countries will account for 75 percent of the world’s population at that time.

Some of the populous countries expected to fall below the replacement fertility level by 2050 include Bangladesh, India, Indonesia, Mexico, South Africa and Turkey. Looking further into the future, below replacement fertility is expected in 184 countries by the end of the century, with the global fertility rate falling below two births per woman.

It is certainly difficult to imagine rapid transitions to low fertility in today’s high-fertility countries, such as Chad, Mali, Niger and Nigeria, where average rates are more than six births per woman. However, rapid transitions from high to low fertility levels have happened in diverse social, economic and political settings.

With social and economic development, including those forces favouring low fertility, and the changing lifestyles of women and men, the transition to below replacement fertility in nearly all the remaining countries with high birth rates may well occur in the coming decades of the 21st century.

A question to our readers: Do you think this is plausible? What do you think this world would look like?

6 comments:

"Below replacement fertility" is just an average - in practice, if the number of births in your society outnumbers the number of deaths, your society will grow - and the opposite if deaths are bigger.

Basically, a humanity with below replacement fertility would eventually shrink down to where births equal deaths again. That might give us some decades where we have a distorted age distribution, but we'd get over that.

Of course, the farther we get into the future, the weirder things potentially get. Major life extension changes the dynamics even further.

I suspect this is off because it does not account for migration. Look at Europe: many countries there are well below replacement TFR but they continue to grow because of migration. Same with the USA, Canada, Australia.

The pessimistic scenario I suppose is the rise of a selfish gerontocracy that makes life so hard for people of fertile age (because their taxes are all going to pay for pensions and healthcare) that fertility rates are driven down past danger levels. A gently declining population probably isn't such a bad thing in the long run, but a situation where each generation is only half as large as the previous one is going to be very difficult to endure. If anything, the recent history of Japan may be too optimistic a picture for the future of countries that have a similar demographic evolution, but without Japan's advantages of high social cohesion and a highly developed economy.

Brett: If increased longevity is coupled with an extended window for fertility, much could change. What would the demographics be like if people were centenarians, for instance, and could be parents for most of their lifetime? Doubling the size of the window could make many things possible, especially given the general postponement of marriage and childbirth that we see.

Abu: This is not just a matter of migration, but of demographic momentum. Fertility rates in some countries might be sub-replacement, but populations might still be coasting on the basis of high fertility in earlier years.